Understanding SPS Light Requirements

[CalciumReef]

How are you guys judging when to change Mh bulb?By observing coral growth?Or taking the age of bulb?

[acura007]

This is a little hard to say.. Every1 has their own pref..

Manufacturer says 8mths, but they can sure last longer depending on the K.

6.5k can last for years according to many in US. While > 10k said to last abt 1.5-2yr on 2ft depth.. then again.. intensity gone by then.

[Aged Salt]

A few things I look for when it's time to change MH's/actinics are:

1)extra growth of coralline algae on my panes

2)darkening of my coral's color

3)coral tips lose their "pop" & flouresence

Bob

[aquabeAnz]

This is from XM 10k SE bulb.

> SPS that shows orange/red colour, needs 550-600 nm spectrum of the light.

> SPS that shows purple/blue colour, needs 310-380 nm spectrum of the light.

> SPS that shows blue/green colour, needs 380-470 nm spectrum of the light.

>SPS that shows green/yellow colour, needs 430-490 nm spectrum of the light.

> SPS that shows yellow colour, needs 440-500 nm spectrum of the light.

>SPS that shows Red/Orange colour, needs 500-540 nm spectrum of the light.

so does it make sense to put blue/green SPS lower since the XM SE 10,000K bulb peaks at this relevant range?

if so, that means by checking out the chart of the bulbs we buy, whichever spectrum the bulb peaks or cover mostly, we can be sure that the associated SPS can be placed lower in the tank?

OR just simply whichever range the bulb we use peak or cover, that is the right bulb to get for that relevant colored SPS, nothing to do with the height that we place the SPS?

sorry, i also blur liao..

[blueheaven]

This is almost equivalent to saying that green plants will have low photosynthesis level in green light as it reflects green light.

But not all SPS colours come from the zooxathellae alone.

Some is produced as protection against UV light

And I believe, to a certain extent that SPS can change to suit their conditions. Its like blasting a green SPS with green light, so they'll change to absorb the other spectrum of light instead.

I've seen frags from the same colonies turn out differently in different reefer's tanks under different light spectrums

[madmac]

> SPS that shows orange/red colour, needs 550-600 nm spectrum of the light.

> SPS that shows purple/blue colour, needs 310-380 nm spectrum of the light.

> SPS that shows blue/green colour, needs 380-470 nm spectrum of the light.

>SPS that shows green/yellow colour, needs 430-490 nm spectrum of the light.

> SPS that shows yellow colour, needs 440-500 nm spectrum of the light.

>SPS that shows Red/Orange colour, needs 500-540 nm spectrum of the light.

Excerpted from this article by Sanjay Joshi : Photosynthesis and Photoadaptation, in the paragraph on 'Spectral distribution of light', ...

As light passes through the water column, it is attenuated exponentially, and this attenuation is not uniform across all wavelengths. So the water acts as a “filter,” reducing the spectrum of light that penetrates it. As depth increases, the waveband of light that penetrates narrows. The shorter wavelengths (reds and yellows) are the first to be absorbed, and the blue light penetrates the deepest. At a depth of 1 meter, only 50 to 60 percent of the higher wavelength light (600 to 700 nm) penetrates the water, and at a depth of 10 meters less than 10 percent of the higher wavelength light penetrates. By comparison, 92 to 97 percent of the irradiance in the 400 to 575 nm range is transmitted at 1 meter in depth, and 40 to 50 percent of the available spectrum in the range of 400 to 550 nm penetrates to depths of 10 meters (Jerlov 1976). Most of the SPS corals are found in waters less than 15 meters deep, but our reef aquariums are usually 24 to 30 inches deep. So, we cannot rely on water to create the difference in spectral distribution in the tank and have to rely on the bulbs to provide a “correct” spectral distribution.

I'm trying to understand this better... by explaining, so bear with me if I interpret wrongly... I think what Sanjay is trying to say... to your questions :

so does it make sense to put blue/green SPS lower since the XM SE 10,000K bulb peaks at this relevant range?

... it doesn't matter how low you go, so long as you meet the spectrum the coral needs and provided you don't go over 2.5 feet deep

if so, that means by checking out the chart of the bulbs we buy, whichever spectrum the bulb peaks or cover mostly, we can be sure that the associated SPS can be placed lower in the tank?

, yes as above.

OR just simply whichever range the bulb we use peak or cover, that is the right bulb to get for that relevant colored SPS, nothing to do with the height that we place the SPS?

same questions phrase differently. yes, but not < 2.5'